In a third day of outages, BlackBerry service disruption has hit the United States and Canada, the company has said.

BlackBerry users have once again taken to social networking sites and microblogging sites like Twitter and Facebook to air their grievances, disgust and frustration at the downed network, which began to falter over three days ago.

Reuters reports that the BlackBerry maker, Research in Motion, has advised some clients that it was "dealing with a BlackBerry outage in the Americas, similar to service disruptions that have cropped up in other parts of the world".

In the early hours of the morning, BlackBerry users in Canada began experiencing difficulty with the service, as residents in the United States also suffered as the day broke.

Research in Motion, which had not previously explained why the fault had occurred, leaving mobile network operators like T-Mobile and Vodafone in their respective regions to communicate with customers, made a statement yesterday:

"The messaging and browsing delays being experienced by BlackBerry users in Europe, the Middle East, Africa, India, Brazil, Chile and Argentina were caused by a core switch failure within RIM’s infrastructure. Although the system is designed to failover to a back-up switch, the failover did not function as previously tested.

As a result, a large backlog of data was generated and we are now working to clear that backlog and restore normal service as quickly as possible. We apologize for any inconvenience and we will continue to keep you informed."

The company has over 70 million BlackBerry users worldwide. While the problems initially affected only BlackBerry Internet Service (BIS) consumer users, BlackBerry Enterprise Service (BES) users who are on a private, corporate domain, appear unaffected.

It is thought that at least two-thirds, if not three-quarters of all BlackBerry subscribers have been affected by the three-day outage.

Users have been left without data services, from browsing, email and BlackBerry Messenger, the company's instant messaging solution used predominately by younger consumers.